Welcome to my astronomy blog, I dedicate myself to the simplest form of amateur astronomy which requires only portable equipments.

Saturday, July 21, 2007

20070721 Solar

Got good sky, it's very blue, very hard to come by in Hong Kong these years, but seeing is no good, I guess 2-3/10 in best moments, transparency is superb at 8-9/10 with little cloud around. It's a great prominence day.

Full disc captured by Borg 45ED II at prime focus, and then go for high power for prominences with 3x barlows, I usually use 2x but this time I used 3x due to the good transparent sky. High transparency sky enables me to use faster shutter and lower gain, thus lower noise at high effective focal ratio.